The White House said Thursday evening that President Biden was "somber" and "outraged" after receiving news of two suicide bombings in Kabul, Afghanistan, that killed 13 U.S. servicemembers. 

During a press briefing Thursday, White House press secretary Jen Psaki said that it is "maybe the worst day of your presidency" if you lose military servicemen.

“I would say that anyone who has watched the president up close ... knows that putting the lives of service men and women at risk and those decisions that you have to make as commander in chief weigh heavily on him,” Psaki said.

Biden learned of the bombings that killed American troops on Thursday morning while in the Situation Room meeting with his national security team, the White House said.

The president was meeting with the team at 9:15 a.m. to hear intelligence, security, and diplomatic updates on the evolving situation in Afghanistan and was told about the attacks when he arrived in the room. 

"The initial reports of the attacks came in as members of his national security team were gathering in the situation room for a regular meeting with the president, so they were just gathering and sitting down, gathering in the room," Psaki told reporters.  "As the president arrived in the situation room, one of the first updates he received, of course, were on the attacks."

Biden received "regular updates as they learned more information" from the ground and was in "constant contact" with Defense Secretary Austin, Secretary of State Antony Blinken, and National Security adviser Jake Sullivan.

The president never had a second meeting with the entire national security team following the morning meeting.

The president's initial public schedule on Thursday was in flux for most of the day. He was scheduled to meet with Israel’s new prime minister, Naftali Bennett, in the morning but the meeting was rescheduled for Friday after it was postponed without an update for a few hours. He also canceled an afternoon virtual meeting with governors.

He delivered remarks before Psaki held a briefing, which was also postponed.

Biden in remarks on Thursday said the U.S. would carry out its plans to withdraw its troops from Afghanistan by Aug. 31, while vowing to strike back against the group responsible for the attacks.

Pentagon officials said two suicide bombers, determined to be affiliated with ISIS, were involved in the attack.